Status of JRC reference measurements of radioactivity to realise the becquerel

The Radionuclide Metrology group of JRC performs reference measurements of activity and nuclear decay characteristics in support of the common measurement system for radioactivity, as stipulated in Art. 8 of the Euratom Treaty. Primary standardisations of activity performed at the JRC and National Metrology Institutes (NMI) are used at a global scale to establish radioactivity measurements in a traceable manner to the SI unit becquerel. To ensure equivalence of national standards, the NMIs and the JRC participate in key comparisons of their primary standardisation measurements of a common mononuclidic solution. The Bureau International des Poids et Mesures (BIPM) in Sèvres (F) issues a report in which the Key Comparison Reference Value (KCRV) is calculated from a mean of the laboratory results, as well as a Degree of Equivalence (DoE) of each participating laboratory to the KCRV. Thus, the SI unit becquerel is established and international equivalence is demonstrated. Recently, the BIPM published final reports on various key comparisons, which validates standardisation work performed earlier at the JRC and other NMIs. This report gives an overview the corresponding key comparison results.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard